Original Manuscript
Relationship of Systolic Blood Pressure and Body Mass Index With Left Ventricular Mass and Mass Index in Adolescents
Angiology 1-8 ª The Author(s) 2015 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/0003319715573102 ang.sagepub.com
Cengiz Ozturk, MD1, Mustafa Aparci, MD2, Mehmet Karaduman, MD3, Sevket Balta, MD4, _ MD1 Turgay C ¸ elik, MD1, and Atilla Iyisoy,
Abstract Prevalence of hypertension (HT) is growing among children and adolescents. Its diagnosis is commonly ignored as it does not produce any end-organ damage in adolescents. We evaluated whether the blood pressure (BP) and confounding factors were related to myocardial mass increase; an earlier representative of HT; among adolescents. We have demonstrated that heart rate, body mass index (BMI), left ventricular mass (LVM), interventricular septum, and LV mass indexed to body surface area (BSA) and height significantly increased as the category of BP increased. We have also showed that the systolic BP (SBP), diastolic BP (DBP), and BMI were significantly correlated with the LVM and LVM indexed to BSA and height. Linear regression analysis revealed a significant relationship between SBP, BMI, and LVM, LVM indexed to BSA and height. Hypertension may cause myocardial hypertrophy even at a young age. Height is an alternative and practical way of determining the left ventricular mass index (LVMI) in adolescents. The BMI is significantly related to LVM and LVMI as well as SBP and DBP are. The results support that overweight and obesity should be controlled strictly in the management of HT in a young population. Keywords systolic blood pressure, body mass index, left ventricular mass, left ventricular mass index, adolescents
Introduction Obesity has long been recognized as a risk factor for hypertension (HT).1 Although the physiological mechanisms that modulate the effects of obesity on blood pressure (BP) are not fully elucidated, epidemiological data that link increased body mass index (BMI) to higher BP are remarkably consistent across different populations.2 Overweight and obese children are known to face significantly increased risk for HT as well as adults.2 The prevalence of high BP among adolescents is increasing, in concert with the childhood obesity epidemic, and the increases of both high BP and obesity are greater among children. Measures of target organ damage, especially cardiac hypertrophy indicate a significant increase in risk of cardiovascular (CV) events among adult patients with HT. Left ventricular mass (LVM) is an independent risk factor for prediction of CV events. Longitudinal data, although limited, indicate that both childhood obesity and high BP are associated with higher LVM in young adulthood. Linear growth is the major determinant of cardiac growth in children and that excess weight may lead to the acquisition of LVM beyond that expected from normal growth. In contrast to adults with HT, the BP in childhood that predicts future CV disease has not been clearly defined. Few studies have investigated the determinants of LVM in
young patients with HT. The development of obesity may be a significant, and possibly modifiable, risk factor for developing left ventricular hypertrophy (LVH) and HT, risk factors for CV morbidity and mortality.3 We evaluated whether the BP and confounding factors were related to myocardial mass increase; an earlier representative of HT induced organ damage among adolescents.
Materials and Methods The study population was composed of apparently healthy 19 year old patients. They had been undergone physical and echocardiographic examination as a standard procedure of pre-test screening. Data was obtained by retrospectively analysis of medical archives. Physical examination included the 1
Department of Cardiology, Gulhane Military Medical Faculty, Ankara, Turkey Department of Cardiology, Etimesgut Military Hospital, Ankara, Turkey 3 Department of Internal Medicine, Etimesgut Military Hospital, Ankara, Turkey 4 Department of Cardiology, Eskisehir Military Hospital, Eskis¸ ehir, Turkey 2
Corresponding Author: Sevket Balta, Department of Cardiology, Eskisehir Military Hospital, Vis¸ nelik Mah., Atatu¨rk Cd. 26020, Akarbas¸ ı, Eskisehir, Turkey. Email: [email protected]
Downloaded from ang.sagepub.com at University of Sussex Library on September 27, 2015
2
Angiology
measurement of height, weight, and heart rate, systolic (SBP) and diastolic BP (DBP). The BMI (kg/m2) and body surface area (BSA, m2 ¼ 0.20247 height0.725 weight0.425) of individuals was calculated.4 Transthoracic echocardiography was performed by an experienced cardiologist using an echocardiography device (Vivid 7, GE Medical Systems, Horten, Norway) with a 3S probe. Echocardiography had been performed by one cardiologist. Left ventricular internal diameters at systole and diastole, ejection fraction, and thickness of interventricular septum (IVS) and posterior wall, diameters of aorta, aortic valve, left atrium measured by M-Mod echocardiography were measured. LV mass of patients was calculated by Devereux formula.5 LVM was indexed to BSA and height. Patients with bicuspid aortic valve, abnormally dilated aorta, aortic coarctation, moderate or severe valvular regurgitation or stenosis, left or right ventricular dilatation, were excluded from the study. All the patients were male. The study was conducted in accordance with the Helsinki Declaration. The study was approved by the local ethics committee. Reliability tests performed by Cochran test using the first consecutive thirty measurements of left ventricular indices. Intraclass coefficient was .958 with a P < .001.
Measurement of BP
rate, thickness of LV IVS and PW, LVM, LVM indexed to BSA and height significantly increased as the BP category raised to Pre-HT and HT. Distribution of LVM and LVM indexed to BSA and height according to BP category was revealed in Figure 1. Weight and Aortic sinus diameter tended to be increased but not statistically significant. SBP was significantly correlated with LVM (R ¼ .259, R2 ¼ .067, adjusted R2 ¼ .065, P < .001); LVM indexed to BSA (R ¼ .252, R2 ¼ .064, adjusted R2 ¼ .062, P < .001); and LVM indexed to height (R ¼ .261, R2 ¼ .068, adjusted R2 ¼ .066, P < .001; Figure 2). The BMI was also significantly correlated with LVM (R ¼ .422, R2 ¼ .178, adjusted R2 ¼ .177, P < .001); LVM indexed to BSA (R ¼ .197, R2 ¼ .039, adjusted R2 ¼ .037, P < .001); and LVM indexed to height (R ¼ .426, R2 ¼ .181, adjusted R2 ¼ .179, P < .001; Figure 3). In correlation analysis we founded that weight, SBP, DBP, BMI were significantly correlated with LVM; SBP, DBP, BMI, Weight were positively correlated with the LVM indexed BSA; and the SBP, DBP, and BMI were significantly correlated with LVM indexed to height. In stepwise linear regression analysis we observed all those factors were positively correlated with the LVM and LVM indexed to BSA and height except the weight (Table 2).
Discussion
Blood pressure was measured from the left arm using the brachial artery by using a validated automated oscillometric BP device (HEM-7223-E, Omron Healthcare Co. Ltd, Kyoto, Japan). Normal BP was defined SBP
Relationship of Systolic Blood Pressure and Body Mass Index With Left Ventricular Mass and Mass Index in Adolescents
Angiology 1-8 ª The Author(s) 2015 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/0003319715573102 ang.sagepub.com
Cengiz Ozturk, MD1, Mustafa Aparci, MD2, Mehmet Karaduman, MD3, Sevket Balta, MD4, _ MD1 Turgay C ¸ elik, MD1, and Atilla Iyisoy,
Abstract Prevalence of hypertension (HT) is growing among children and adolescents. Its diagnosis is commonly ignored as it does not produce any end-organ damage in adolescents. We evaluated whether the blood pressure (BP) and confounding factors were related to myocardial mass increase; an earlier representative of HT; among adolescents. We have demonstrated that heart rate, body mass index (BMI), left ventricular mass (LVM), interventricular septum, and LV mass indexed to body surface area (BSA) and height significantly increased as the category of BP increased. We have also showed that the systolic BP (SBP), diastolic BP (DBP), and BMI were significantly correlated with the LVM and LVM indexed to BSA and height. Linear regression analysis revealed a significant relationship between SBP, BMI, and LVM, LVM indexed to BSA and height. Hypertension may cause myocardial hypertrophy even at a young age. Height is an alternative and practical way of determining the left ventricular mass index (LVMI) in adolescents. The BMI is significantly related to LVM and LVMI as well as SBP and DBP are. The results support that overweight and obesity should be controlled strictly in the management of HT in a young population. Keywords systolic blood pressure, body mass index, left ventricular mass, left ventricular mass index, adolescents
Introduction Obesity has long been recognized as a risk factor for hypertension (HT).1 Although the physiological mechanisms that modulate the effects of obesity on blood pressure (BP) are not fully elucidated, epidemiological data that link increased body mass index (BMI) to higher BP are remarkably consistent across different populations.2 Overweight and obese children are known to face significantly increased risk for HT as well as adults.2 The prevalence of high BP among adolescents is increasing, in concert with the childhood obesity epidemic, and the increases of both high BP and obesity are greater among children. Measures of target organ damage, especially cardiac hypertrophy indicate a significant increase in risk of cardiovascular (CV) events among adult patients with HT. Left ventricular mass (LVM) is an independent risk factor for prediction of CV events. Longitudinal data, although limited, indicate that both childhood obesity and high BP are associated with higher LVM in young adulthood. Linear growth is the major determinant of cardiac growth in children and that excess weight may lead to the acquisition of LVM beyond that expected from normal growth. In contrast to adults with HT, the BP in childhood that predicts future CV disease has not been clearly defined. Few studies have investigated the determinants of LVM in
young patients with HT. The development of obesity may be a significant, and possibly modifiable, risk factor for developing left ventricular hypertrophy (LVH) and HT, risk factors for CV morbidity and mortality.3 We evaluated whether the BP and confounding factors were related to myocardial mass increase; an earlier representative of HT induced organ damage among adolescents.
Materials and Methods The study population was composed of apparently healthy 19 year old patients. They had been undergone physical and echocardiographic examination as a standard procedure of pre-test screening. Data was obtained by retrospectively analysis of medical archives. Physical examination included the 1
Department of Cardiology, Gulhane Military Medical Faculty, Ankara, Turkey Department of Cardiology, Etimesgut Military Hospital, Ankara, Turkey 3 Department of Internal Medicine, Etimesgut Military Hospital, Ankara, Turkey 4 Department of Cardiology, Eskisehir Military Hospital, Eskis¸ ehir, Turkey 2
Corresponding Author: Sevket Balta, Department of Cardiology, Eskisehir Military Hospital, Vis¸ nelik Mah., Atatu¨rk Cd. 26020, Akarbas¸ ı, Eskisehir, Turkey. Email: [email protected]
Downloaded from ang.sagepub.com at University of Sussex Library on September 27, 2015
2
Angiology
measurement of height, weight, and heart rate, systolic (SBP) and diastolic BP (DBP). The BMI (kg/m2) and body surface area (BSA, m2 ¼ 0.20247 height0.725 weight0.425) of individuals was calculated.4 Transthoracic echocardiography was performed by an experienced cardiologist using an echocardiography device (Vivid 7, GE Medical Systems, Horten, Norway) with a 3S probe. Echocardiography had been performed by one cardiologist. Left ventricular internal diameters at systole and diastole, ejection fraction, and thickness of interventricular septum (IVS) and posterior wall, diameters of aorta, aortic valve, left atrium measured by M-Mod echocardiography were measured. LV mass of patients was calculated by Devereux formula.5 LVM was indexed to BSA and height. Patients with bicuspid aortic valve, abnormally dilated aorta, aortic coarctation, moderate or severe valvular regurgitation or stenosis, left or right ventricular dilatation, were excluded from the study. All the patients were male. The study was conducted in accordance with the Helsinki Declaration. The study was approved by the local ethics committee. Reliability tests performed by Cochran test using the first consecutive thirty measurements of left ventricular indices. Intraclass coefficient was .958 with a P < .001.
Measurement of BP
rate, thickness of LV IVS and PW, LVM, LVM indexed to BSA and height significantly increased as the BP category raised to Pre-HT and HT. Distribution of LVM and LVM indexed to BSA and height according to BP category was revealed in Figure 1. Weight and Aortic sinus diameter tended to be increased but not statistically significant. SBP was significantly correlated with LVM (R ¼ .259, R2 ¼ .067, adjusted R2 ¼ .065, P < .001); LVM indexed to BSA (R ¼ .252, R2 ¼ .064, adjusted R2 ¼ .062, P < .001); and LVM indexed to height (R ¼ .261, R2 ¼ .068, adjusted R2 ¼ .066, P < .001; Figure 2). The BMI was also significantly correlated with LVM (R ¼ .422, R2 ¼ .178, adjusted R2 ¼ .177, P < .001); LVM indexed to BSA (R ¼ .197, R2 ¼ .039, adjusted R2 ¼ .037, P < .001); and LVM indexed to height (R ¼ .426, R2 ¼ .181, adjusted R2 ¼ .179, P < .001; Figure 3). In correlation analysis we founded that weight, SBP, DBP, BMI were significantly correlated with LVM; SBP, DBP, BMI, Weight were positively correlated with the LVM indexed BSA; and the SBP, DBP, and BMI were significantly correlated with LVM indexed to height. In stepwise linear regression analysis we observed all those factors were positively correlated with the LVM and LVM indexed to BSA and height except the weight (Table 2).
Discussion
Blood pressure was measured from the left arm using the brachial artery by using a validated automated oscillometric BP device (HEM-7223-E, Omron Healthcare Co. Ltd, Kyoto, Japan). Normal BP was defined SBP
